This invention pertains to a wrist strain relief device for association with a hand held tool. More particularly, the invention pertains to a forearm-engaging member associated with a meat trimming knife to reduce pressure on the wrist of a user and reduce the likelihood of the user incurring the disability commonly known as carpal tunnel syndrome.
The meat industry has many uses for a hand held trimming knife wherein a manually-applied downward force and knife movement causes a motor-driven knife blade to perform a cutting operation. Such a knife is used in trimming fat from meat and can also be used for slicing and removing meat from bones. One showing of a knife of this general type is in the Bettcher U.S. Pat. No. 4,170,063 wherein the knife has a manually-grippable cylindrical body and a knife mounting at one end which mounts a circular knife blade. The circular knife blade is motor-driven, such as by an air motor mounted within the knife body.
The knife is normally used by manually gripping the knife body and exerting a downward force to press the circular knife blade downwardly against the meat and the knife is drawn toward the operator to perform the desired cutting, such as fat trimming.
The use of the meat trimming knife has resulted in a common workers' compensation disability, known as carpal tunnel syndrome. The carpal tunnel is a channel in the wrist through which important nerves, blood vessels and tendons pass into the hand. Carpal tunnel syndrome is caused by compression of the median nerve as it lies beneath the flexor retinaculum in the carpal tunnel. The flexor retinaculum is made up of two bands of ligaments which surround the wrist. The use of the meat trimming knife results in pressure at the wrist and the whole hand can be bent backwards. This pressure and bending can result in carpal tunnel syndrome.
Carpal tunnel syndrome results in unusual sensations in either the wrist or several fingers of the hand, such as burning, itching, prickling, or gingling, with usually some sensory disturbance in the fingers. In severe cases, certain muscles of the thumb can atrophy and there is an over-all weakness of the hand. The median nerve can also be affected. Carpal tunnel syndrome has resulted in payment of hundreds of thousands of dollars a year in workers' compensation injuries for at least one meat packer and this problem is prevalent throughout the meat packing industry.
The invention to be described hereinafter enables the use of a meat trimming knife in a manner which will remove pressure from the wrist to minimize the likelihood of carpal tunnel syndrome.